The present invention relates generally to measuring the straightness of a rod and more particularly to a system and method for measuring the straightness of a nuclear fuel rod.
The straightness of nuclear fuel rods is determined in a quality control inspection step after the rods have been loaded with fuel pellets and their ends sealed (such as by welding on end caps) but before the rods have been used in the makeup of a fuel assembly. Rods that do not meet straightness specifications are rejected and salvaged. The use of an out-of-specification fuel rod may well result in improper rod-to-rod spacing in the fuel assembly with a degradation in fuel performance in the reactor, and/or difficulty in fitting together the fuel rods and other components into a fuel assembly.
Conventional techniques for determining fuel rod straightness include manually rolling the rod on a surface table, stopping the rotation at various times, and visually determining (such as with the use of feeler gauges) if any rod is bent.